[scribe] show stylus hover icon

Show a pointer when the stylus is hovering on the display.
Currently, pointers are only used for ‘pointer’ touch
devices such as trackpad and they are not used for
‘direct’ touch devices such as touchscreen or stylus.
As internal stylus devices are supposed to be ‘direct’,
add an implementation for direct touch devices.

Test: Manual Test
Bug: b/215436642
Change-Id: I0c57c40c496246b35b155a679959e12edb75d1e6